Abstract

Isotope abundance ratios play an important role in astronomy and planetary sciences, providing insights in the interstellar chemistry, the origin and evolution of the Solar System. As we firmly step into the era of exoplanet characterization, detecting isotopologues in exoplanet atmospheres becomes feasible, suggesting great potentials of tracing the formation history of planets. In this talk, I will present the first detection of 13CO isotopologue in atmospheres of two young substellar objects, the super-Jupiter YSES -1b and the brown dwarf 2M0355. The distinct CO isotopologue ratios measured in the atmosphere of the super-Jupiter (12CO/13CO_{30) and the brown dwarf (12CO/13CO}100) may hint to their different formation pathways. I will also discuss some future prospects of isotopologue measurements in exoplanets and their link to constraining planet formation.